This invention relates generally to medical devices, and more particularly to devices for engaging and extracting or removing stones, calculi or the like from the biliary or urinary tracts.
A variety of tracts or ducts in the body are subject to the development of stones, calculi or the like. (For convenience, such stones, calculi and the like may sometimes be referred to herein by the words xe2x80x9cstonexe2x80x9d or xe2x80x9cstonesxe2x80x9d. For example, stones may develop in the kidneys and migrate down the ureters. Sometimes such stones become lodged in the ureters, requiring surgical intervention for their removal. Similarly, gallstones may develop in the gallbladder, and migrate down the biliary duct (the common bile duct), through the ampulla of Vater, and out the Sphincter of Oddi into the duodenum. As with kidney stones, such stones occasionally become lodged in the biliary duct, the pancreatic duct or the ampulla of Vater. Indeed, gallstones can be of such a size as to be unable to pass through the Sphincter of Oddi. In either case, surgical intervention is again required for their removal.
A number of surgical devices are known for engaging and extracting or removing stones from the biliary or urinary tracts. However, the satisfactory introduction of such devices into the ampulla of Vater or the associated ducts may require the surgical cutting of the papilla of Vater (in which the Sphincter of Oddi is formed). Such cutting is commonly performed with sphincterotomes, in particular, papillotomes. Such cutting devices are typically used in conjuction with an endoscope.
A very useful papillotome is disclosed in U.S. Pat. No. 5,024,617 (J. Karpiel, Jun. 18, 1991). The specification of the patent notes that a survey conducted by the American Society for Gastrointestinal Endoscopy revealed that the most common major complication from endoscopic sphincterotomy was bleeding. The specification of the patent further notes that the vast majority of such bleeding typically results when the retroduodenal artery is cut. Other major complications include pancreatitis, perforation and cholangitis. The device disclosed in the patent is intended to enhance the control a physician has while performing a sphincterotomy, and thereby reduce the risk of such injury to the patient from the procedure. While the device disclosed in the patent appears to achieve this desired reduction in risk, healing of the papilla of Vater after cutting can be problematic. Moreover, the physical arrangement of useful surgical cutters may hinder visualization of the site being cut. Further, U.S. Pat. No. 5,383,849 (F. Johlin, Jr., Jan. 24, 1995) notes that, when a cannula is used in endoscopic retrograde cholangiopancreatography (ERCP), difficulty is sometimes encountered in the attempt to successfully cannulate (that is, enter with a cannula) the desired duct among the bile and pancreatic ducts.
Attempts have been made to avoid the problems associated with cutting of the papilla of Vater. For example, catheter devices including inflatable balloons have been used to temporarily dilate the Sphincter of Oddi (or other biliary structure) so as to permit the passage of retrieval baskets or extraction balloons therethrough. One such biliary balloon dilator is sold by Wilson-Cook Medical Inc., Winston-Salem, N. C., under the name Quantum TTC(copyright). That dilator includes a biliary dilation balloon carried on a dual-lumen catheter, one lumen serving for the introduction of an inflation medium into the dilation balloon, and the other lumen accepting a conventional 0.89 mm (0.035 in.) guide wire therein. An associated apparatus (the Quantum Biliary Inflation Device, or Q.B.I.D.(trademark)) is used to control the inflation pressure or inflation volume of the balloon.
During use, the deflated balloon of the device is first positioned via an endoscope across the structure to be dilated, for example, across the Sphincter of Oddi, and then inflated to dilate the structure. The balloon is then deflated and removed from the structure, and the device removed from the patient. It has been found that the Sphincter of Oddi remains dilated for a few minutes before it closes; during the time it is dilated, a retrieval basket or extraction balloon is introduced through the endoscope and through the dilated Sphincter, into engagement with the stones to be removed.
An example of an extraction balloon device useful for this purpose is the Tri-Ex(trademark) Triple Lumen Extraction Balloon sold by Wilson-Cook Medical Inc. The device includes a triple lumen catheter which carries on it a distending latex balloon. One lumen serves to deliver an inflation medium to the balloon, a second serves to contain a conventional guide wire, and a third permits the introduction of a contrast medium distal (above) or proximal (below) the balloon. The volume of inflation medium is determined by a premeasured syringe connected to the first lumen. In use, the deflated balloon of the device is introduced through the Sphincter of Oddi (for example, via the endoscope) past the stones, then inflated and employed to urge the stones towards and out the Sphincter of Oddi. Other retrieval balloons are of course useful for this purpose as well.
A variety of retrieval baskets are known for the endoscopic removal of stones and other foreign bodies from both the biliary and urinary tracts. Such baskets can be exemplified by the WEB(trademark) Extraction Basket sold by Wilson-Cook Medical Inc., which includes a plurality of filaments or wires constructed of a shape memory material. Nitinol in a superelastic state is an example of a shape memory material. As a further example, U.S. Pat. No. 4,295,464 (A. A. Shihata, Oct. 20, 1981) discloses a ureteric stone extractor having two ballooned catheters, in particular, an inner dislodger catheter slidable within a relatively larger outer dilator catheter. The dislodger catheter includes a lumen having a stiffening metal stylet disposed in it. The balloon of the dilator catheter must remain inflated during use of the extractor, thus preventing visualization of the stone by an endoscope.
Unfortunately, the successful use of many of such devices is often not possible. In particular, the closure time of the papilla of Vater (that is, the time in which the Sphincter of Oddi closes after dilation by the balloon) is so short that the Sphincter of Oddi often closes before the dilation balloon catheter is removed from the patient and the retrieval basket or extraction balloon is introduced and advanced to the Sphincter. Even when the guide wire has been advanced through the Sphincter, cannulation of the extraction balloon through the collapsed Sphincter may still be difficult. Moreover, guide wires are not generally used with retrieval baskets; unless the basket is introduced quickly enough, the dilation of the Sphincter is a wasted effort. Further, since the dilation balloon is typically axially aligned with the line-of-sight of the endoscope, ensuring that the balloon actually lies across the Sphincter of Oddi or other structure may be difficult as well.
It would be highly advantageous to have devices which permitted the engagement and extraction or removal of stones, calculi or the like from the biliary tract, the urinary tract or other body structure without requiring any surgical cutting of body tissue. It would also be highly advantageous to have devices which permitted the introduction of a retrieval basket, extraction balloon or the like quickly enough to take advantage of the time the Sphincter of Oddi or other structure remained dilated, so as to permit the ready passage of the basket or balloon through the Sphincter and allow the ready observation of the engagement of the stones by the basket or balloon via the endoscope. It would further be highly advantageous to have devices which permitted the basket, balloon or the like to urge the stones through the Sphincter of Oddi or other structure while it was still dilated. Finally, it would be highly advantageous to have dilation balloon devices which affirmatively ensured the position of the dilation balloon with respect to the Sphincter of Oddi or other body structure during its dilation.
The foregoing problems are solved and a technical advance is achieved in illustrative devices for dilating sphincters or other structures in the body of a human or veterinary patient, and engaging and extracting or removing stones, calculi or the like (hereinafter, xe2x80x9cstonesxe2x80x9d) from the body of a human or veterinary patient, for example, from the biliary or urinary tract of the patient. The purpose of the device is to provide firstly means of dilating a sphincter or tract opening, and secondly means of extracting or retrieving stones from a tract beyond the sphincter or opening. Thus, in the present invention, a device comprises a catheter shaft, a first expandable apparatus fixed on the catheter shaft for dilating the tract entrance, and a stone retrieving apparatus associated with the catheter shaft for urging the stone through the tract entrance. The stone retrieving apparatus may be a second expandable apparatus. Either (or both) of the first and second expandable apparatus may be a balloon or may be a basket or cage. Both may be balloons, each on a discrete tube in a telescoping arrangement, or upon a single catheter device. The first expandable apparatus may be retained in the expanded position or condition during stone retrieval, or it may be deflated or collapsed and removed.
More particularly, in a first embodiment, the device of the present invention comprises a plural lumen catheter shaft which carries affixed to it both an appropriate inflatable dilation balloon, and a suitable inflatable retrieval balloon dimensioned and adapted for urging the stones through the biliary or urinary tract of the patient. Preferably, the dilation balloon is of nondistendable (nonstretchable) material, such as polyethylene terephthalate (PET), and the retrieval balloon is of distendable material, such as latex. Affixing both balloons to a single catheter shaft, as in the first embodiment, advantageously minimizes the profile of the device, advantageously minimizes the manipulative steps required for introduction and advancement of the device, and eliminates the time previously required to remove the dilation balloon from the patient and introduce a separate extraction balloon into the patient. The relatively small profile of the device readily allows the deflated balloons to be advanced along a previously inserted guide wire, for example, advanced through the Sphincter of Oddi or other structure or entrance to a small tract such as a ureter. When the dilation balloon lies fully across the Sphincter or other entrance, the dilation balloon is inflated so as to dilate the Sphincter or other entrance; the dilation balloon is then deflated so as to allow observation of the extraction balloon through the Sphincter or entrance via an endoscope. The extraction balloon is advanced until it has been moved to a position past the stones, and then is inflated and manipulated to urge the stones through the biliary or urinary tract of the patient.
This is not to say that the extraction balloon is itself employed to fully remove the stones from the patient. For example, with gallstones it is likely sufficient merely to urge the stones past the Sphincter of Oddi into the duodenum, and allow the stones to pass from the body naturally after that. Similarly, urging kidney stones from the ureters to the bladder is likely to be sufficient to ensure the subsequent elimination of the stones from the body. Moreover, it should be noted that, in general, it is anticipated that the endoscope will not pass through the Sphincter of Oddi or other structure; only the catheter shaft, dilation balloon and extraction balloon will.
In a second embodiment, the device of the present invention comprises a catheter shaft having a dilation balloon fixed on it, and a reversibly collapsible extraction basket slidably received in, and extendable from, the catheter shaft. The basket is preferably connected to a control member disposed in a lumen in the catheter shaft. The control member need not be a discrete member; for example, when the basket comprises a plurality of wires, the control member can comprise extending portions of the wires extending through the catheter shaft. While the device is preferably highly flexible, the basket and/or the control member provide sufficient stiffness to permit the basket (contained in the catheter shaft) and the deflated dilation balloon to be advanced through the Sphincter of Oddi or duct or ureter entrance until the balloon lies thereacross. The balloon is inflated to dilate the Sphincter or entrance, and then deflated to allow observation (via endoscope, through the dilated Sphincter or other structure) of the extension of the basket from the catheter shaft and into engagement with the stones. The stones are captured by the basket or otherwise urged by manipulation of the basket through the Sphincter of Oddi or entrance and into the digestive or urinary tract. Again, it is expected that, in general, the endoscope will not pass through the Sphincter of Oddi or entrance dilated.
In a third embodiment, the device of the present invention comprises a dumbbell-shaped or wasp-waisted balloon catheter for dilating a sphincter or duct or ureter entrance in a patient, preferably for dilating the Sphincter of Oddi. The device comprises an inflatable dilation balloon carried on a catheter shaft, the balloon having proximal and distal inflatable portions, and an intermediate inflatable portion between the proximal and distal portions. Unlike balloons previously used to anchor catheters in the body, all three portions of the dilation balloon are inflatable to a significant degree. More particularly, the intermediate inflatable portion of the balloon has an inflated diameter which is suited for the temporary dilation of the sphincter, while the proximal and distal inflatable portions have inflated diameters which are greater than the inflated diameter of the intermediate portion. Inflation of the balloon automatically centers the balloon in the sphincter, establishing a predetermined amount of dilation of the sphincter. The several portions of the balloon are preferably continuously formed, and are preferably in fluid communication with one another. Conveniently, the balloon defines a single inflation chamber, such that there are no walls or partitions separating the proximal, distal and intermediate portions of the dilation balloon. Separate inflation chambers in each of the several balloon portions are also contemplated within the present invention, of course.
A fourth embodiment provides two telescopically arranged tubes wherein the first tube is fitted with a first expandable apparatus for dilating a sphincter or duct or ureter entrance, and wherein the second tube is fitted with a second expandable apparatus for extracting or retrieving stones from the tract. The first tube may be inside or outside of the second tube. Either or both of the first and second expandable apparatus may be a balloon, a basket or a xe2x80x9ccagexe2x80x9d. If the expandable apparatus are balloons, the first or dilator balloon is made of a nondeformable material that is capable of deforming the sphincter or tract opening when the balloon is inflated. The second or extraction balloon is made of a material that has to be deformable when the balloon is inflated to adapt to the tact in which the stones are located and to be able to withdraw the stones.
The telescopic arrangement of two tubes each having an expandable apparatus has also the advantage of minimizing the manipulative steps required for introduction and advancement of the device, and eliminates the time previously required to remove a dilation device from the patient and introduce a separate extraction balloon in the patient. The telescopic arrangement is therefore well suited to a situation where a sphincter, having been previously dilated, would collapse rapidly before a surgeon could proceed with the extraction of the stone.
Each of the embodiments of the device of the present invention is particularly advantageous over prior dilation and extraction devices in one or more of a variety of ways. For example, the devices of the present invention may permit the engagement and extraction or removal of stones, calculi or the like from the biliary tract, the urinary tract or other body structure without requiring any surgical cutting of body tissue, for example, of the Sphincter of Oddi. The devices of the present invention may also permit the introduction of an associated retrieval basket, extraction balloon or the like quickly enough to take advantage of the time the Sphincter of Oddi or tract entrance remained dilated, so as to permit the ready passage of the basket or balloon through the Sphincter and allow the ready observation of the engagement of the stones by the basket or balloon via the endoscope. The devices of the present invention may also permit their associated basket, balloon or the like to urge the stones through the Sphincter of Oddi or other entrance structure while it was still dilated. Finally, the devices of the present invention may affirmatively ensure the position of the dilation balloon with respect to the Sphincter of Oddi or other body structure during its dilation.
As indicated above, the device of the present invention possesses significant advantages over prior devices.